The present disclosure relates to decurler devices for correcting (decurling) a curl of a sheet and image forming apparatuses including the same.
Image forming apparatuses including a decurler device are known. The decurler device corrects (decurls) a curl of a sheet. The decurler device is arranged downstream of a fusing section in a sheet conveyance direction in an image forming apparatus. In an image forming apparatus, the sheet is allowed to pass through the fusing section in order to fuse a toner image transferred to the sheet. The sheet, which is heated and pressed in the fusing section, may tend to curl. In the image forming apparatus, the sheet is ejected to an exit port. When the sheet curls, the accommodation capacity of the exit port for sheets may reduce.
Curls of a sheet are roughly divided into an upward curl and a downward curl. The upward curl means upward curling of a lead edge of the sheet, and the downward curl means downward curling of a lead edge of the sheet. In order to address both the upward curl and the downward curl, a technique which vertically turns over the decurler device is known. Further, a technique to make nip pressure between rollers variable is known. According to this technique, the effect of curl correction (decurling) is adjustable.